Pantelbymos



P. WRADY.

(No Model() AIR PUMP.

UNITED STATES PANTELEYMON VRADY, Oli"` ST. PETERSBURG, RUSSIA.

PATENT OFFICE.

AIR-PUMP.

SPECIFICATION forming part of Letters Patent No. 340,928, dated April27,1886.

Application filed September 24, 1885. Serial No. 178,008. (No model.)

To @ZZ whom it may concern:

Be it known that I, PANTELEYMON WRADY, a subject of the Czar of Russia,and residing at St. Petersburg, Russia, have invented certainImprovements in Vacuum- Pumps, of which the following is aspecification.

My improved vacuum-pump is more especially designed for exhausting theair from glass bulbs ofincandescent electric lamps, although it may beapplied to other uses where a vacnum is to be produced.

In the accompanying drawings, Figure l is a vertical section of myimproved pump, and

Figs. 2 and 3 are detached sectional views, drawn to an enlargedscale,of one of the valves.

The main portion of the pump consists of a cylinder or tube, a, aboutone hundred and twenty-tive centimeters long, with an inside diameter of12.7 centimeters. The top of the cylinder a is closed by a cover, b,through which pass the rods cof the piston D, and also the rod e, formanipulating the stop-cock hereinafter described. This covering bcarries a support, f, for bearings for the axis of a pinion. g, gearinginto a rack on the piston-rod c, the shaft of the pinion being providedwith a suitable crank-handle, h. On the same support f are bearings fora guide-roller, j, to support the back of the piston-rod c. The lowerend of the cylinder a is closed by a bottom piece, 7c, the interiorsurface of which within the cylinder is made concave and the face of thepiston d is made correspondinglyrounded to accurately fit the concavebottom of the cylinder when the piston isin its lowest position, so thatthe volume of oil then contained inthe space cannot exceed two hundredcubic millimeters.

The piston is provided with a suitable number of packing-pieces ofleather pressed between the bottom of the piston and its screwring i.Within the piston is a cavity, Z, into which oil may be poured.

The pistou-rod c may be screwed or otherwise secured to the piston d,and through the center of the rod is avery fine conduit, at the upperend of which is a stop-cock, r. As illustrated more fully in Figs. 2 and3, the plug s of this valve has two passages at right angles to eachother, and a side opening is'formed in the pistonrod, so that when theplug s of the valve is turned to the position illustrated in Fig. 2 thistine conduit in the piston-rod will be open to the interior of thecylinder a. Through the bottom piece, k, is bored a central conduitclosed by a stop-cock, m, and opening at its lower end into a smallreservoir, n, for collecting the drops of oil. This reservoir n isprovided with a bent tube, o, to which is attached a glass tube, p,having a communication with the globe from which the air is to beexhausted. This glass tube phas a side opening closed by a smallindiauubber reservoir, q, filled with oil, and provided with an internalspiral spring, by which it may be kept distended, and in the tube pisformed an enlargement, p', the object of this iexible reservoirp and itsenlargementp being,as hereinafter described, to serve as an indicator ofdegree to which the lamp has been exhausted.

The operation of the apparatus is as follows: The stop-cocks m and rbeing closed, and the piston d being at the bottom of the cylinder a,and the lamp to be exhausted being tightly connected with the end of thetubep, the piston d is rst caused to ascend by the turning of the crankh, and when it has arrived at the end of its stroke the stopcock m isopened. The air in the lamp-globe and piping is thus rareed by beingdrawn into the exhaustcylinder a. The stopcock m is then closed, and thecool; ropened by means of the rod e, which is connected byacrank to theplug of the cock, as illustrated in Figs. Zand 3. rIhe piston d is thencaused to descend until it reaches the bottom of its movement, so thatthe air below the piston in the cylinder c will passthrough the conduitin the rod c of the pump-piston as the latter descends. When the pistonreaches the bottom of its movement-,the coclm' is closed again and thepiston raised, and when the latter reaches the top of the cylinder thecock m is then opened again, so that a further rarefaction of the air inthe lampglobe is produced, and the operation is repeated unt-il thedesired vacuum is obtained. A few pistonstrokes inthe pump of thedimensions described are sufticient to produce a vacuum of about oneseven-millionth of the atmospherical pressure.

In order to know when the desired vacuum has been obtained, I make useof the indicating devices above referred to and consisting oi theoil-reservoir q and pipe p, with its en- IOC largement p', the operationbeing` that when the cock m is opened and the air in the tubingtherefore suddenly drawn into the cylinder a, a drop of oil will beprojected from the top of Jthe reservoir q into the enlargement p of theglass tube p, and this Will be repeated until the amount of air in thetubing,` is so small as to have no visible effect on the oil When thecock m is suddenly opened. In order that the action of an insignificantquan tity of air still remaining` in the lamp-globe may neverthelessshow its effect on the oil7 I diminishthc volume of oildrop moving inthe glass tube p by stretching the india-rubber res ervoir q by hand,thereby increasing,` the ca pacity of the reservoir.

It Will be understood that by making the cylinder a longer a stillgreater rarefaction of air'may be obtained, and this degree of rarefaction may be still further increased by heating thelamp-globe whilethepunip is in action.

I claim as my invention- 1. The hercin-described vacuum-pump7 consistingof a cylinder having a cock at its lower end and a piston provided witha fine conduit and cock therein, as described.

2. The combination of an exhaust-purnp with a vacuum-indicating deviceconsisting of a tube communicating with the chamber to be exhausted, andhaving an oil-reservoir, substantially as specified.

3. The combination of the cylinder a of a'

